In the access technology of the radio communication, there is an access method based on the fast indication. The burst data of the access can often be divided into several sections, the next section of the information is transmitted normally only when the responses of the data in the preceding sections (For example, an acquisition response, and the like) have been received. Normally, this type of responses only has responses with two values of 1 and −1, or with three values of 1, −1, and 0. Wherein, only one value, for example 1, is used for the indication acquired successfully and allowed to access. Thus, the more precise control function can not be sufficient.
Please refer to FIG. 1 and FIG. 2, in the access of the physical random access channel (PRACH) and the physical common packet channel (PCPCH) of the up channels in WCDMA, the fast indication method is used for indicating the prefix acquisition situation. For the physical random access channel (PRACH), the acquisition indication channel (AICH) is used to indicate the acquisition on the down link. For PCHCH, the access prefix acquisition indication channel (AP-ACH) and the conflict detection/channel assignment indication channel (CD/CA-ICH) are used. For the physical random access channel (PRACH), a value evaluated by the open loop power is firstly used by the user equipment as the transmission prefix of the initial transmission power. If the acquisition indication information of the down link acquisition indication channel (AICH) has not been received (or the received acquisition indication information is 0), then another prefix will continuously be transmitted subsequently by adding power ΔP0. If the received acquisition indication is −1, then it will exit the procedure and report to the upper layer. If the received acquisition indication is 1, then the information section will be transmitted by using a preamble power bias ΔPp-m corresponding to the last successful access.
In this way, because an error may be reach +/−12 dB under an extreme situation of the open loop power evaluation, and considering the throughput of the physical random access channel (PRACH), ΔP0 being not taken very small, and the affect of the channel fading, AP power which is accessed successfully at last and the acquisition probability at the said power may change significantly. If this is taken as a reference power to transmit the signals of the information section by increasing the power bias ΔPp−m (once this parameter is assigned by the high layer, all of the user equipment will use this fix parameter in a long period unless reassigning), the variation range of the power of the information section may also be very large, causing the comprehensive performance of accessing the entire physical random access channel (PRACH) worse.
The access procedure for the physical common packet channel (PCPCH) is slightly similar as that of the physical random access channel (PRACH), a transmitted access prefix AP is evaluated firstly by the user equipment based on the open loop power. If the acquisition indication information of the down link prefix acquisition indication channel (AP-AICH) is not received (or the acquisition indication is 0), then the prefix will continuously be transmitted by using power bias ΔP0. If the received acquisition indication is 1, then the conflict detection prefix (CD-P) will be transmitted by using the same power.
If the corresponding conflict detection prefix (CD-P) is not received in the conflict detection/channel assignment indication channel (CD/CA-ICH), then the procedure will be exited and reported to the upper layer. If it is received, then the power control prefix and the message section are transmitted by using the power bias of ΔPp−m.
For the same reason as that for accessing the physical random access channel (PRACH), AP power which is accessed successfully at last of the physical common packet channel (PCPCH) and the acquisition probability based on the said power may change significantly. In this way, the conflict detection transmitted subsequently and the power control prefix and the initial power of the message section will also change significantly. Thus, it causes the comprehensive performance of the entire link worse.
The frame format of the acquisition indication channel (AICH) in WCDMA is shown in FIG. 3, wherein,
      a    j    =            ∑              s        =        0            15        ⁢                  ⁢                  AI        s            ⁢              b                  s          ,          j                    
The value of acquisition indication AI is taken as 1, 0, and −1 based on the result of the acquisition. S represents the sequence number of the characteristic code. See Table 1 for the value of bs and j (Table 1 is a characteristic code table of the acquisition indication channel):
TABLE 1sbs,0, bs,1 . . . , bs,310111111111111111111111−1−111−1−111−1−111−1−11121111−1−1−1−11111−1−1−1−111311−1−1−1−11111−1−1−1−11111411111111−1−1−1−1−1−1−1−111511−1−111−1−1−1−111−1−1111161111−1−1−1−1−1−1−1−1111111711−1−1−1−111−1−11111−1−11181111111111111111−1−1911−1−111−1−111−1−111−1−1−1−1101111−1−1−1−11111−1−1−1−1−1−11111−1−1−1−11111−1−1−1−111−1−11211111111−1−1−1−1−1−1−1−1−1−11311−1−111−1−1−1−111−1−111−1−1141111−1−1−1−1−1−1−1−11111−1−11511−1−1−1−111−1−11111−1−1−1−1sbs,0, bs,1 . . . , bs,310111111111111111−1−111−1−111−1−111−1−1211−1−1−1−11111−1−1−1−13−1−1−1−11111−1−1−1−1114111111−1−1−1−1−1−1−1−15−1−111−1−1−1−111−1−111611−1−1−1−1−1−1−1−111117−1−1−1−111−1−11111−1−18−1−1−1−1−1−1−1−1−1−1−1−1−1−1911−1−111−1−111−1−11110−1−11111−1−1−1−11111111111−1−1−1−11111−1−112−1−1−1−1−1−1111111111311−1−11111−1−111−1−114−1−111111111−1−1−1−1151111−1−111−1−1−1−111
Thus, it is stipulated in the current protocol that the acquisition indication channel can only have three types of indications of 0, 1, and −1 for a certain characteristic code. Wherein, only the acquisition indication “1” is used to indicated that the accessing is allowed, however, more precise power control information cannot be provided.
The same format as that used for the acquisition indication channel (AICH) can be used to transmit the prefix acquisition indication channel (AP-ACH).
For the conflict detection/channel assignment indication channel (CD/CA-ICH),
      a    j    =                    ∑                  i          =          0                15            ⁢                          ⁢                        CDI          i                ×                  b                                    s              i                        ,            j                                +                  ∑                  k          =          0                15            ⁢                          ⁢                        CAI          k                ×                  b                                    s              k                        ,            j                              wherein, CDIi and CAIk generate the value, refer to Table 2 (Table 2 is a generation table for CDIi and CAIi in the conflict detection/channel assignment indication channel);
TABLE 2Conflictdetectionprefix iChanneltransmittedcharacteristicassignmentCharacteristicby usercodesequencecodeequipment iCDIisinumber kCAIksk0+1/010+1/001−1/01−1/02+1/032+1/083−1/03−1/04+1/054+1/045−1/05−1/06+1/076+1/0127−1/07−1/08+1/098+1/029−1/09−1/010+1/01110+1/01011−1/011−1/012+1/01312+1/0613−1/013−1/014+1/01514+1/01415−1/015−1/0
Therefore, only two indications of 1 and −1 are used to indicate that the conflict detection has been acquired, and it is unable to provide to the user equipment the more precise control indication.
Because the power fluctuation range of the current physical random access channel (PRACH) and physical common packet channel (PCPCH) is very large when acquiring, however, only one indication is used for permitting access when the acquisition is successful, thus, it causes the fluctuation range of the subsequent information transmission power, which takes the said power as a power bias reference, of the subsequent sections also being very large, and causing the whole access performance degrading.